A theory-driven intervention delivered by email to promote physical activity in women who are overweight or obese: Participants’ perspectives on acceptability and usability within the context of a three-arm parallel group randomized controlled trial

Abstract Background: Insufficient physical activity and excess weight increase illness risk for women. Email-delivered interventions may be a solution for offering accessible, cost-effective, brief support to women to increase their engagement in physical activity. This study explored participants’ perspectives of the acceptability and usability of a theory-driven, email-delivered intervention coupled with a wearable activity monitor designed to promote physical activity in women who were insufficiently active and overweight/obese. Methods: In this three-arm parallel group randomized controlled trial (unblinded), participants allocated to the main intervention arm received a fully automated intervention consisting of: (a) six weekly emails, (b) a Polar A300 activity monitor (with access to the Polar website and companion smartphone application), and (c) a copy of the Canadian physical activity guidelines for adults (18-64 years). Email content, informed by self-determination theory, was designed to enhance autonomous motivation for physical activity through fostering perceptions of competence, autonomy, and relatedness by sharing motivational and behaviour change techniques to promote needs satisfaction. Post-intervention, participants completed an acceptability survey containing open- and closed-ended questions online. Descriptive and content analyses were performed for responses to closed- and open-ended questions, respectively. Results: Data from 14 women (age range=18-63 years, mean body mass index=31.3±5.8 kg/m2) who received the main intervention and completed the post-intervention survey were analyzed. Qualitative data indicated most were satisfied with the intervention and appreciated that emails prompted self-reflection, kept them on track and accountable, provided informational support, and were non-pressuring. Further, it suggested the monitor was “enjoyable” and “helpful;” quantitative data corroborated this as 71.4% said the monitor was “very valuable/absolutely valuable,” 71.7% would “very probably/definitely” still use one, and 85.7% wore it ≥5 days/week for ≥8 hours/day and checked it “occasionally/frequently/very frequently.” However, potential threats to acceptability were noted, including “long” and “text-heavy” emails, lack of personal contact, and cumbersome, non-aesthetic monitors. Conclusions: Results suggest this self-determination theory-driven email-delivered intervention may be an acceptable low-contact approach to help promote physical activity in women who are overweight or obese and insufficiently active, although improvements are warranted and studies ascertaining its effectiveness are needed. Nonetheless, results may inform the development or refinement of similar interventions in other contexts. Trial Registration: This trial was registered at ClinicalTrials.gov (ID: NCT03601663, Date: July 26, 2018; http://clinicaltrials.gov/ct2/show/NCT03601663).